Assay of factor XII in human plasma using prekallikrein or the chromogenic peptide S-2222 as substrates--significance of the functional state of plasma kallikrein.
Thromb Res
; 54(3): 197-205, 1989 May 01.
Article
em En
| MEDLINE
| ID: mdl-2787541
ABSTRACT
Factor XII was assayed in acetone-treated and kaolin-activated human citrated plasma (total plasma dilution 1.0 + 0.3 v/v during activation with kaolin, 1.8 mg/ml incubate). Measurements were performed with the tetrapeptide Bz-Ile-Glu-Gly-Arg-pNa (S-2222) and with prekallikrein as substrates. The correlation of both methods to another S-2222 based method recently described was good, r = 0.90 and 0.85 for the two methods respectively. Under the assay conditions used, FXIIa was present as a S-2222 amidase that could be blocked by corn inhibitor, whereas plasma kallikrein was found to be present partly as an amidase blocked by a low concentration of soybean trypsin inhibitor, and partly in a functional state not inhibited and adding to the measured level of FXII. The presence of benzamidine 0.7 to 2.1 mM during acetone treatment increased the measured level of FXII assayed both as prekallikrein activator and as S-2222 amidase.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Oligopeptídeos
/
Fator XII
/
Pré-Calicreína
Limite:
Humans
Idioma:
En
Revista:
Thromb Res
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
Noruega